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Publications (4)6.84 Total impact

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    ABSTRACT: Molecular characterization studies of a diverse collection of avian influenza viruses (AIVs) have demonstrated that AIVs' greatest genetic variability lies in the HA, NA, and NS genes. The objective here was to quantify the association between geographical locations, periods of time, and host species and pairwise nucleotide variation in the HA, NA, and NS genes of 70 isolates of H5N1 highly pathogenic avian influenza virus (HPAIV) collected from October 2005 to December 2007 from birds in Romania. A mixed-binomial Bayesian regression model was used to quantify the probability of nucleotide variation between isolates and its association with space, time, and host species. As expected for the three target genes, a higher probability of nucleotide differences (odds ratios [ORs] > 1) was found between viruses sampled from places at greater geographical distances from each other, viruses sampled over greater periods of time, and viruses derived from different species. The modeling approach in the present study maybe useful in further understanding the molecular epidemiology of H5N1 HPAI virus in bird populations. The methodology presented here will be useful in predicting the most likely genetic distance for any of the three gene segments of viruses that have not yet been isolated or sequenced based on space, time, and host species during the course of an epidemic.
    Full-text · Article · Sep 2013 · Avian Diseases
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    ABSTRACT: RESUMEN Modelo de la asociación entre espacio, tiempo y especies hospedadoras con variaciones de los genes HA, NA y NS de virus de la influenza aviar H5N1 altamente patógenos aislados de aves en Rumania entre los años 2005 al 2007. Los estudios de caracterización molecular de una colección diversa de virus de la influenza aviar (AIV) han demostrado que la mayor variabilidad genética de estos virus se encuentra en los genes HA, NA, y NS. El objetivo fue cuantificar la asociación entre la localización geográfica, los períodos de tiempo, y las especies hospedadoras con la variación en los pares de nucleótidos dentro de los genes HA, NA y NS de 70 aislamientos de virus de la influenza aviar altamente patógenos H5N1 (HPAIV) recolectados entre octubre de 2005 a diciembre del 2007 de aves en Rumania. Se utilizó un modelo de regresión bayesiana mixto binomial para cuantificar la probabilidad de variación de nucleótidos entre los aislamientos y su relación con el espacio, el tiempo, y las especies hospedadoras. Como se esperaba, para los tres genes estudiados, una mayor probabilidad de diferencias de nucleótidos (odds ratio [OR] > 1) se encontró entre los virus recolectados de lugares con grandes distancias geográficas entre sí, los virus detectados a lo largo de grandes períodos de tiempo, y los virus derivados de diferentes especies. El enfoque de este modelo en el presente estudio puede resultar útil para comprender aún más la epidemiología molecular del virus de la influenza aviar H5N1 altamente patógeno en poblaciones de aves. La metodología presentada, puede ser útil para predecir durante el curso de una epidemia, la distancia genética más probable para cualquiera de los tres segmentos de genes de virus que aún no han sido aislados, o secuenciados con base en el espacio, en el tiempo y en las especies hospedadoras.
    Full-text · Article · Apr 2013 · Avian Diseases
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    ABSTRACT: In this study, we have analyzed 23 PCV2 ORF2 sequences recovered from wild boar population in Romania. The PCV2 sequences were originated from different geographical regions in Romania, and collected between 2008 and 2009 during the classical swine fever virus (CSFV) surveillance campaign. Complete open reading frame 2 (ORF2) nucleotide sequences were obtained and compared with sequences mainly from European and Asian isolates. The Romanian sequences were identified as belonging to previously described clusters 2a and 2b, with high degree of heterogeneity (PCV2 ORF2 nucleotide homology ranged between 90.1% and 100%). Interestingly, for cluster 2a, the majority of the sequences (8 from a total number of 9) clustered mainly with the Asian isolates (especially China, but also India and South Korea), with three exceptions from Europe previously reported in Germany, Belgium and The Netherlands.
    No preview · Article · Mar 2011 · Research in Veterinary Science
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    ABSTRACT: This study reports the first incursion into European poultry of H5N1 highly pathogenic notifiable avian influenza A (HPNAI) viruses from clade 2.3.2 that affected domestic poultry and wild birds in Romania and Bulgaria, respectively. Previous occurrences in Europe of HPNAI H5N1 in these avian populations have involved exclusively viruses from clade 2.2. This represents the most westerly spread of clade 2.3.2 viruses, which have shown an apparently expanding range of geographical dispersal since mid-2009 following confirmation of infections in wild waterfowl species in Mongolia and Eastern Russia. During March 2010, AI infection was suspected at post-mortem examination of two hens from two backyard flocks in Tulcea Country, Romania. HPNAI of H5N1 subtype was confirmed by reverse transcription polymerase chain reaction (RT-PCR). A second outbreak was confirmed 2 weeks later by RT-PCR, affecting all hens from another flock located 55 km east of the first cluster. On the same day, an H5N1 HPNAI virus was detected from a pooled tissue sample collected from a dead Common Buzzard found on the Black Sea coast in Bulgaria. Detailed genetic characterization of the haemagglutinin gene revealed the cleavage site of the isolates to be consistent with viruses of high pathogenicity belonging to clade 2.3.2 of the contemporary Eurasian H5N1 lineage. Viruses from a clade other than 2.2 have apparently spread to wild birds, with potential maintenance and spread through such populations. Whilst the scale of threat posed by the apparent westward spread of the clade 2.3.2 viruses remains uncertain, ongoing vigilance for clinical signs of disease as part of existing passive surveillance frameworks for AI, and the prompt reporting of suspect cases in poultry is advised.
    Full-text · Article · Nov 2010 · Transboundary and Emerging Diseases